Evaluation of drought tolerance indices for screening bread wheat genotypes in drought stress conditions

For this aim the present study was conducted on 10 winter bread wheat in 2010-11 farming year under various humidity conditions (without stress and terminal drought stress) in Ardabil Region. Study genotypes were evaluated in the form of complete randomized blocks design with three recurring. Evaluation of genotypes for susceptibility and tolerance against drought stress was done based on indices such as GMP, STI and MP and a great difference was observed between genotypes and these indices, these indices provided a different categorization of two indices namely SSI and TOL for tolerance and/or susceptibility against stress. Results from statistic analyses, stability analysis and yield comparison of study genotypes showed that genotypes 4, 5 and 8 were superior to other genotypes and are recommendable for the conditions of normal irrigation and drought stress after anthesis in arid and semiarid regions. Investigating the indices of tolerance against stress demonstrated that index STI has more generality than others.